/*=====================================================================*
 *                   Copyright (C) 2011 Paul Mineiro                   *
 * All rights reserved.                                                *
 *                                                                     *
 * Redistribution and use in source and binary forms, with             *
 * or without modification, are permitted provided that the            *
 * following conditions are met:                                       *
 *                                                                     *
 *     * Redistributions of source code must retain the                *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer.                                       *
 *                                                                     *
 *     * Redistributions in binary form must reproduce the             *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer in the documentation and/or            *
 *     other materials provided with the distribution.                 *
 *                                                                     *
 *     * Neither the name of Paul Mineiro nor the names                *
 *     of other contributors may be used to endorse or promote         *
 *     products derived from this software without specific            *
 *     prior written permission.                                       *
 *                                                                     *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND              *
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,         *
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES               *
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE             *
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER               *
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,                 *
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES            *
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE           *
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR                *
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF          *
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT           *
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY              *
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE             *
 * POSSIBILITY OF SUCH DAMAGE.                                         *
 *                                                                     *
 * Contact: Paul Mineiro <paul@mineiro.com>                            *
 *=====================================================================*/

#include "qfunc.h"
#include "prating.c"

float
qfunc (const float*                     alpha,
       unsigned int                     n_labels,
       float                            logbeta,
       float*                           dlogbeta,
       float*                           ddlogbeta,
       const float*                     pz,
       const Rating*                    ratings,
       unsigned int                     n_ratings,
       const Distribution*              priorlogbeta,
       int                              symmetric,
       float                            hq)
{
  float q = hq;

  *dlogbeta = 0;
  *ddlogbeta = 0;

  for (unsigned int i = 0; i < n_ratings; ++i)
    {
      for (unsigned int j = 0; j < n_labels; ++j)
        {
          float dlogbetatmp;
          float ddlogbetatmp;

#define alphafunc(_k)                                           \
  ({                                                            \
    (_k == j) ? -1.0 :                                          \
    (symmetric && _k < j)                                       \
        ? alpha[ratings[i].worker * n_labels * n_labels +       \
                _k * n_labels +                                 \
                j]                                              \
        : alpha[ratings[i].worker * n_labels * n_labels +       \
                j * n_labels +                                  \
                _k];                                            \
  })

          q += pz[j] * 
               logprating (ratings[i].rating,
                           alphafunc,
                           logbeta,
                           dlogbetatmp,
                           ddlogbetatmp,
                           n_labels);

          *dlogbeta += pz[j] * dlogbetatmp;
          *ddlogbeta += pz[j] * ddlogbetatmp;
        }
#undef alphafunc
    }

  q += distribution_logpdf (priorlogbeta, logbeta);
  *dlogbeta += distribution_dlogpdf (priorlogbeta, logbeta);
  *ddlogbeta += distribution_ddlogpdf (priorlogbeta, logbeta);

  return q;
}

void
dqfunc (float*                           dalpha,
        const float*                     alpha,
        unsigned int                     n_labels,
        float                            logbeta,
        const float*                     pz,
        const Rating*                    ratings,
        unsigned int                     n_ratings,
        int                              symmetric)
{
  for (unsigned int i = 0; i < n_ratings; ++i)
    {
      for (unsigned int j = 0; j < n_labels; ++j)
        {
          float tmpdalpha[n_labels];

#define alphafunc(_k)                                           \
  ({                                                            \
    (_k == j) ? -1.0 :                                          \
    (symmetric && _k < j)                                       \
        ? alpha[ratings[i].worker * n_labels * n_labels +       \
                _k * n_labels +                                 \
                j]                                              \
        : alpha[ratings[i].worker * n_labels * n_labels +       \
                j * n_labels +                                  \
                _k];                                            \
  })

          dlogpratingdalpha (tmpdalpha,
                             ratings[i].rating,
                             alphafunc,
                             logbeta,
                             n_labels);

          for (unsigned int k = 0; k < n_labels; ++k)
            {
              if (k == j)
                {
                  /* do nothing ... */
                }
              else if (symmetric && k < j) 
                {
                  dalpha[ratings[i].worker * n_labels * n_labels +
                         k * n_labels +
                         j] += 
                    pz[j] * tmpdalpha[k];
                }
              else
                {
                  dalpha[ratings[i].worker * n_labels * n_labels +
                         j * n_labels +
                         k] += 
                    pz[j] * tmpdalpha[k];
                }
            }
        }
#undef alphafunc
    }
}
